The proposed work is concerned with the mechanisms governing the generation of pattern and form in biological systems. At the cellular level, we are primarily concerned with the time-course of sorting-out phenomena, and the manner in which these depend on the magnitudes of cellular affinities and the rates of motility. These results can be applied to an understanding of specific congenital malformations arising from genetic modifications of affinity and motility parameters. We also expect to apply our sorting models to problems of molecular architecture; specifically to the determination of tertiary structure of globular proteins given the primary structure. Finally, we intend to continue our work into the control of differentiation by the genome, and the general problem of the genotype-phenotype dualism.